Final answer:
The correct oxidation half-reaction for the chemical equation 2Mg + O² -> 2MgO is Mg -> Mg²⁺ + 2e⁻, which is option (a). Magnesium loses electrons, which is indicative of the oxidation process in a redox reaction.
Step-by-step explanation:
The student is asking to identify the oxidation half-reaction in the chemical equation 2Mg + O² -> 2MgO. For oxidation-reduction (redox) reactions, we look at how electrons are transferred. The substance that loses electrons is being oxidized. Oxidation numbers are used, resembling ion charges, to help describe this electron transfer. In the given equation, magnesium (Mg) is oxidized as it reacts with oxygen (O²).
The complete oxidation half-reaction for magnesium transforming into magnesium oxide is: Mg -> Mg²⁺ + 2e⁻. When magnesium atoms lose electrons, they become positively charged ions indicated by the symbol Mg²⁺, and the loss of two electrons is shown as +2e⁻. This half-reaction shows the oxidation process where magnesium loses electrons.
Correct Answer
The correct oxidation half-reaction that matches the format and process described above is option (a): Mg²⁺ + 2e⁻ -> Mg.